Edaravone, a free radical scavenger, protects components of the neurovascular unit against oxidative stress in vitro

Oxidative Stress and Age-Related Tumors

Oxidative stress is the result of the imbalance between reactive oxygen and nitrogen species (RONS), which are produced by several endogenous and exogenous processes, and antioxidant defenses consisting of exogenous and endogenous molecules that protect biological systems from free radical toxicity. Oxidative stress is a major factor in the aging process, contributing to the accumulation of cellular damage over time. Oxidative damage to cellular biomolecules, leads to DNA alterations, lipid peroxidation, protein oxidation, and mitochondrial dysfunction resulting in cellular senescence, immune system and tissue dysfunctions, and increased susceptibility to age-related pathologies, such as inflammatory disorders, cardiovascular and neurodegenerative diseases, diabetes, and cancer. Oxidative stress-driven DNA damage and mutations, or methylation and histone modification, which alter gene expression, are key determinants of tumor initiation, angiogenesis, metastasis, and therapy resistance. Accumulation of genetic and epigenetic damage, to which oxidative stress contributes, eventually leads to unrestrained cell proliferation, the inhibition of cell differentiation, and the evasion of cell death, providing favorable conditions for tumorigenesis. Colorectal, breast, lung, prostate, and skin cancers are the most frequent aging-associated malignancies, and oxidative stress is implicated in their pathogenesis and biological behavior. Our aim is to shed light on the molecular and cellular mechanisms that link oxidative stress, aging, and cancers, highlighting the impact of both RONS and antioxidants, provided by diet and exercise, on cellular senescence, immunity, and development of an antitumor response. The dual role of ROS as physiological regulators of cell signaling responsible for cell damage and diseases, as well as its use for anti-tumor therapeutic purposes, will also be discussed. Managing oxidative stress is crucial for promoting healthy aging and reducing the risk of age-related tumors.

Synthesis and Neuroprotective Evaluation of Substituted Indanone/Benzofuranone and Piperidine Hybrids

Based on the neuroprotection of butylphthalide and donepezil, a series of indanone/benzofuranone and piperidine hybrids were designed and synthesized for assessment of their neuroprotective activities, aiming to enhance the bioavailability and therapeutic efficacy of natural phthalide analogues. Within this study, it was observed that most indanone derivatives bearing 1-methylpiperidine in the tail segment demonstrated superior neuroprotective effects on the oxygen glucose deprivation/reperfusion (OGD/R)-induced rat primary neuronal cell injury model in vitro compared to benzofuranone compounds. Among the synthesized compounds, 11 (4, 14, 15, 22, 26, 35, 36, 37, 48, 49, and 52) displayed robust cell viabilities in the OGD/R model, along with favorable blood-brain barrier permeability as confirmed by the parallel artificial membrane permeability assay. Notably, compound 4 showed significant neuronal cell viabilities within the concentration range of 3.125 to 100 μM, without inducing cytotoxicity. Further results from in vivo middle cerebral artery occlusion/R experiments revealed that 4 effectively ameliorated ischemia-reperfusion injury, reducing the infarct volume to 18.45% at a dose of 40 mg/kg. This outcome suggested a superior neuroprotective effect compared to edaravone at 20 mg/kg, further highlighting the potential therapeutic efficacy of compound 4 in addressing neurological disorders.

Carnosic Acid Shows Higher Neuroprotective Efficiency than Edaravone or Ebselen in In Vitro Models of Neuronal Cell Damage

This study compared the neuroprotective efficacy of three antioxidants-the plant-derived carnosic acid (CA), and two synthetic free radical scavengers: edaravone (ED) and ebselen (EB)-in in vitro models of neuronal cell damage. Results showed that CA protected mouse primary neuronal cell cultures against hydrogen peroxide-induced damage more efficiently than ED or EB. The neuroprotective effects of CA were associated with attenuation of reactive oxygen species level and increased mitochondrial membrane potential but not with a reduction in caspase-3 activity. None of the tested substances was protective against glutamate or oxygen-glucose deprivation-evoked neuronal cell damage, and EB even increased the detrimental effects of these insults. Further experiments using the human neuroblastoma SH-SY5Y cells showed that CA but not ED or EB attenuated the cell damage induced by hydrogen peroxide and that the composition of culture medium is the critical factor in evaluating neuroprotective effects in this model. Our data indicate that the neuroprotective potential of CA, ED, and EB may be revealed in vitro only under specific conditions, with their rather narrow micromolar concentrations, relevant cellular model, type of toxic agent, and exposure time. Nevertheless, of the three compounds tested, CA displayed the most consistent neuroprotective effects.

Experimental Treatment with Edaravone in a Mouse Model of Spinocerebellar Ataxia 1

Edaravone is a mitochondrially targeted drug with a suggested capability to modify the course of diverse neurological diseases. Nevertheless, edaravone has not been tested yet in the context of spinocerebellar ataxia 1 (SCA1), an incurable neurodegenerative disease characterized mainly by cerebellar disorder, with a strong contribution of inflammation and mitochondrial dysfunction. This study aimed to address this gap, exploring the potential of edaravone to slow down SCA1 progression in a mouse knock-in SCA1 model. SCA1^154Q/2Q and healthy SCA1^2Q/2Q mice were administered either edaravone or saline daily for more than 13 weeks. The functional impairments were assessed via a wide spectrum of behavioral assays reflecting motor and cognitive deficits and behavioral abnormalities. Moreover, we used high-resolution respirometry to explore mitochondrial function, and immunohistochemical and biochemical tools to assess the magnitude of neurodegeneration, inflammation, and neuroplasticity. Data were analyzed using (hierarchical) Bayesian regression models, combined with the methods of multivariate statistics. Our analysis pointed out various previously documented neurological and behavioral deficits of SCA1 mice. However, we did not detect any plausible therapeutic effect of edaravone on either behavioral dysfunctions or other disease hallmarks in SCA1 mice. Thus, our results did not provide support for the therapeutic potential of edaravone in SCA1.

Docetaxel-induced cognitive impairment in rats can be ameliorated by edaravone dexborneol: Evidence from the indicators of biological behavior and anisotropic fraction

Objective

This study aimed to investigate the effect of Edaravone Dexborneol (ED) on impaired learning and memory in docetaxel (DTX)-treated rats using cognitive behavior assessments and magnetic resonance diffusion tensor imaging (DTI).

Materials and methods

In total, 24 male Sprague–Dawley rats were divided into control, low-dose DTX (L-DTX) model, and high-dose DTX(H-DTX) model groups, with eight rats in each group, numbered 1–8. The rats were intraperitoneally injected with 1.5 mL of either normal saline (control group), or 3 mg/kg and 6 mg/kg DTX (L-DTX and H-DTX groups, respectively), once a week for 4 weeks. The learning and memory abilities of each group were tested using a water maze. At the end of the water maze test, rats 1–4 in each group were treated with ED (3 mg/kg, 1 mL), and rats 5–8 were injected with an equal volume of normal saline once a day for 2 weeks. The learning and memory abilities of each group were evaluated again using the water maze test, and the image differences in the hippocampus of each group were analyzed using DTI.

Results

(1) H-DTX group (32.33 ± 7.83) had the longest escape latency, followed by the L-DTX group (27.49 ± 7.32), and the Control group (24.52 ± 8.11) having the shortest, with the difference being statistically significant (p < 0.05). (2) Following ED treatment, compared to rats treated with normal saline, the escape latency of the L-DTX (12.00 ± 2.79 vs. 10.77 ± 3.97, p < 0.05), and the H-DTX (12.52 ± 3.69 vs. 9.11 ± 2.88, p < 0.05) rats were significantly shortened. The residence time in the target quadrant of H-DTX rats was significantly prolonged (40.49 ± 5.82 vs. 55.25 ± 6.78, p < 0.05). The CNS damage in the L-DTX rats was repaired to a certain extent during the interval between the two water maze tests (28.89 ± 7.92 vs. 12.00 ± 2.79, p < 0.05). (3) The fractional anisotropy (FA) value of DTI in the hippocampus of rats in the different groups showed variable trends. After treatment with ED, though the FA values of most areas in the hippocampus of rats in L-DTX and H-DTX groups were higher than before, they did not reach the normal level.

Conclusion

ED can ameliorate the cognitive dysfunctions caused by DTX in rats by improving the learning and memory impairment, which is reflected in the recovery of biological behavior and DTI indicators of the hippocampus.

Discovery of novel danshensu derivatives bearing pyrazolone moiety as potential anti-ischemic stroke agents with antioxidant activity

Neuroprotective agents with attenuation of oxidative stress by directly scavenging ROS and indirectly through Keap1-Nrf2 signal pathway activation may be a promising cerebral ischemic stroke therapeutic strategy. In this study, a series of novel danshensu derivatives bearing pyrazolone moieties with dual antioxidant effects were synthesized for the treatment of ischemic stroke. Most compounds exhibited considerable DPPH free radical scavenging ability and neuroprotective activity against H₂O₂-induced oxidative injury in PC12 neuronal cells, without cytotoxicity. Among these target compounds, Del03 displayed the strongest dose-dependent neuroprotective activity in vitro, directly downregulated intracellular ROS levels, and improved the oxidative stress parameters MDA, SOD, and LDH. Del03 also promoted Nrf2 translocation to the nucleus, subsequently increasing the expression of the Nrf2 downstream target HO-1. Molecular docking analysis revealed that Del03 could anchor to the key site of Keap1. Del03 possessed the ability to penetrate blood-brain barrier and displayed good ability on pharmacokinetic properties in rats Del03 possessed good BBB penetration efficiency, suitable pharmacokinetic properties in vivo. Del03 reduced cerebral infarction volume and promoted neurological function in a middle cerebral artery occlusion (MCAO) mouse model at a dose of 20 mg/kg by intravenous injection. The characteristics of Del03 detailed in this study demonstrate its potential as a therapeutic agent in the treatment of ischemic stroke.

Pharmacological Strategies for Stroke Intervention: Assessment of Pathophysiological Relevance and Clinical Trials

OBJECTIVES

The present review describes stroke pathophysiology in brief and discusses the spectrum of available treatments with different promising interventions that are in clinical settings or are in clinical trials.

METHODS

Relevant articles were searched using Google Scholar, Cochrane Library, and PubMed. Keywords for the search included ischemic stroke, mechanisms, stroke interventions, clinical trials, and stem cell therapy.

RESULTS AND CONCLUSION

Stroke accounts to a high burden of mortality and morbidity around the globe. Time is an important factor in treating stroke. Treatment options are limited; however, agents with considerable efficacy and tolerability are being continuously explored. With the advances in stroke interventions, new therapies are being formulated with a hope that these may aid the ongoing protective and reparative processes. Such therapies may have an extended therapeutic time window in hours, days, weeks, or longer and may have the advantage to be accessible by a majority of the patients.

Neuroprotective approach in acute ischemic stroke: A systematic review of clinical and experimental studies

Ischemic stroke is a disease with worldwide economic and social negative effects. It is a serious disease with high disability and mortality. Ionic imbalance, excitotoxicity, oxidative stress, and inflammation are induced during and after ischemic stroke. Cellular dysfunction, apoptosis, and necrosis are activated directly or indirectly mechanisms. The studies about neuroprotection in neurodegenerative diseases have increased in recent years. Data about the mechanisms of progressive molecular improvement in the brain tissue are increasing in acute ischemic stroke. Based on these data, preclinical and clinical studies on new neuroprotective treatments are being designed. An effective neuroprotective strategy can prolong the indication period of recanalization treatments in the acute stage of ischemic stroke. In addition, it can reduce neuronal necrosis and protect the brain against ischemia-related reperfusion injury. The current review has evaluated the recent clinical and experimental studies. The molecular mechanism of each of the neuroprotective strategies is also summarized. This review may help develop future strategies for combination treatment to protect the cerebral tissue from ischemia-reperfusion injury.

Edaravone Inhibits the Production of Reactive Oxygen Species in Phagocytosis- and PKC-Stimulated Granulocytes from Multiple Sclerosis Patients Edaravone Modulate Oxidative Stress in Multiple Sclerosis

Background

Oxidative stress is associated with the pathogenesis of MS. Edaravone (EDV) has been proposed as a therapeutic resource for central nervous system diseases, and it was effective in reducing oxidative stress. However, the antioxidant mechanisms of EDV are poorly studied.

Objective

This study aimed to evaluate the effects of EDV on resting, phagocytosis, and PKC-activated granulocytes derived from MS patients and a healthy control group.

Methods

The effects of EDV on ROS production in phagocytosis (ROS production in the presence of opsonized particles) and PKC-stimulated granulocytes were evaluated in a luminol-dependent chemiluminescence method. Calphostin C was used in some experiments to compare with those of EDV.

Results

EDV inhibited ROS production in phagocytosis of opsonized particles and PKC-stimulated granulocytes from MS patients and healthy control group. In the presence of calphostin C, the inhibition of ROS production was similar to that observed with EDV.

Conclusion

These findings suggest the involvement of EDV on the ROS-PKC-NOX signaling pathways modulating oxidative stress in MS. EDV represents a promising treatment option to control oxidative innate immune response for MS.

Edaravone attenuates neuronal apoptosis in hippocampus of rat traumatic brain injury model via activation of BDNF/TrkB signaling pathway

INTRODUCTION

The purpose of our study was to explore the effects of edaravone on rats with traumatic brain injury (TBI) and investigate the underlying mechanism.

MATERIAL AND METHODS

All rats were separated randomly into 3 groups as follows: sham group (n = 25), TBI group (n = 25), TBI + edaravone group (n = 25). Edaravone was administered intraperitoneally (i.p.) at a dose of 3 mg/kg at 30 min, 12 h, and 24 h after TBI. The neurological impairment and spatial cognitive function were assessed by the neurologic severity score (NSS) and Morris water maze (MWM), respectively. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to determine the expression levels of caspase-3, B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB). Transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay as well as flow cytometry assay was used to determine the apoptosis rate of cells.

RESULTS

Edaravone administration significantly attenuated neurological impairment induced by TBI and promoted cognitive function outcome. The expression of BDNF and TrkB was elevated with treatment of edaravone, which was increased after TBI. The expression of apoptosis related proteins such as caspase-3 and Bax-2 was decreased while that of Bcl-2 was enhanced with edaravone administration following TBI. In addition, edaravone treatment reduced TBI-induced cell apoptosis in the hippocampus.

CONCLUSIONS

Our study showed that administration with edaravone was able to inhibit neuronal apoptosis in the hippocampus in a rat TBI model. The neuroprotective function of edaravone may relate to modulation of the BDNF/TrkB signaling pathway.

Umbilical cord blood cells for the treatment of preterm white matter injury: Potential effects and treatment options

Preterm birth is a global public health problem. A large number of preterm infants survive with preterm white matter injury (PWMI), which leads to neurological deficits, and has multifaceted etiology, clinical course, monitoring, and outcomes. The principal upstream insults leading to PWMI initiation are hypoxia-ischemia and infection and/or inflammation and the key target cells are late oligodendrocyte precursor cells. Current PWMI treatments are mainly supportive, and thus have little effect in terms of protecting the immature brain or repairing injury to improve long-term outcomes. Umbilical cord blood (UCB) cells comprise abundant immunomodulatory and stem cells, which have the potential to reduce brain injury, mainly due to anti-inflammatory and immunomodulatory mechanisms, and also through their release of neurotrophic or growth factors to promote endogenous neurogenesis. In this review, we briefly summarize PWMI pathogenesis and pathophysiology, and the specific properties of different cell types in UCB. We further explore the potential mechanism by which UCB can be used to treat PWMI, and discuss the advantages of and potential issues related to UCB cell therapy. Finally, we suggest potential future studies of UCB cell therapy in preterm infants.

ALS motor neurons exhibit hallmark metabolic defects that are rescued by SIRT3 activation

Motor neurons (MNs) are highly energetic cells and recent studies suggest that altered energy metabolism precede MN loss in amyotrophic lateral sclerosis (ALS), an age-onset neurodegenerative disease. However, clear mechanistic insights linking altered metabolism and MN death are still missing. In this study, induced pluripotent stem cells from healthy controls, familial ALS, and sporadic ALS patients were differentiated toward spinal MNs, cortical neurons, and cardiomyocytes. Metabolic flux analyses reveal an MN-specific deficiency in mitochondrial respiration in ALS. Intriguingly, all forms of familial and sporadic ALS MNs tested in our study exhibited similar defective metabolic profiles, which were attributed to hyper-acetylation of mitochondrial proteins. In the mitochondria, Sirtuin-3 (SIRT3) functions as a mitochondrial deacetylase to maintain mitochondrial function and integrity. We found that activating SIRT3 using nicotinamide or a small molecule activator reversed the defective metabolic profiles in all our ALS MNs, as well as correct a constellation of ALS-associated phenotypes.

Emerging neuroprotective strategies for the treatment of ischemic stroke: An overview of clinical and preclinical studies

Stroke is the leading cause of disability and thesecond leading cause of death worldwide. With the global population aged 65 and over growing faster than all other age groups, the incidence of stroke is also increasing. In addition, there is a shift in the overall stroke burden towards younger age groups, particularly in low and middle-income countries. Stroke in most cases is caused due to an abrupt blockage of an artery (ischemic stroke), but in some instances stroke may be caused due to bleeding into brain tissue when a blood vessel ruptures (hemorrhagic stroke). Although treatment options for stroke are still limited, with the advancement in recanalization therapy using both pharmacological and mechanical thrombolysis some progress has been made in helping patients recover from ischemic stroke. However, there is still a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke to protect the brain from damage prior to and during recanalization, extend the therapeutic time window for intervention and further improve functional outcome. The current review has assessed the past challenges in developing neuroprotective strategies, evaluated the recent advances in clinical trials, discussed the recent initiative by the National Institute of Neurological Disorders and Stroke in USA for the search of novel neuroprotectants (Stroke Preclinical Assessment Network, SPAN) and identified emerging neuroprotectants being currently evaluated in preclinical studies. The underlying molecular mechanism of each of the neuroprotective strategies have also been summarized, which could assist in the development of future strategies for combinational therapy in stroke treatment.

Protective Effect of Edaravone on Cyclophosphamide Induced Oxidative Stress and Neurotoxicity in Rats

BACKGROUND

Cyclophosphamide (CPA) is the most widely prescribed cancer chemotherapeutic agent which shows serious neurotoxic side effect. Generation of reactive oxygen species at the cellular level is the basic mechanism of cyclophosphamide induced neurotoxicity. Edaravone is the synthetic drug used for brain stroke and has potent antioxidant property.

OBJECTIVE

This study aimed to investigate the effect of edaravone on neurobehavioral and neuropathological alteration induced by cyclophosphamide in male rats.

METHODS

Twenty eight Sprague-Dawley rats were equally divided into four groups of seven rats in each. The control group received saline, and other groups were given CPA intraperitoneally (100 mg/kg), CPA (100 mg/kg) intraperitoneally + Edaravone (10 mg/kg) orally, or Edaravone (10 mg/kg) orally for one month.

RESULTS

Our data showed that CPA significantly elevated brain AChE activity in the hippocampal region. A decrease in the total antioxidant capacity and a reduction in the CAT, SOD, and GPX activity occurred in the brains of the rats exposed to CPA. CPA-treated rats showed a significant impairment in long-termmemory and motor coordination. These results were supported by histopathological observations of the brain. Results revealed that administration of edaravone reversed AChE activity alternation and ameliorated behavioral and histopathological changes induced by CPA.

CONCLUSION

This study suggests that co-administration of edaravone with cyclophosphamide may be a useful intriguing therapeutic approach to overcome cyclophosphamide induced neurotoxicity.

Intravenous Edaravone plus Therapeutic Hypothermia Offers Limited Neuroprotection in the Hypoxic-Ischaemic Newborn Piglet

BACKGROUND

Therapeutic hypothermia (TH) is a standard therapy for neonatal hypoxic-ischaemic encephalopathy. One potential additional therapy is the free radical scavenger edaravone (EV; 3-methyl-1-phenyl-2-pyrazolin-5-one).

OBJECTIVES AND METHODS

This study aimed to compare the neuroprotective effects of edaravone plus therapeutic hypothermia (TH + EV) with those of TH alone after a hypoxic-ischaemic insult in the newborn piglet. Anaesthetized piglets were subjected to 40 min of hypoxia (3-5% inspired oxygen), and cerebral ischaemia was assessed using cerebral blood volume. Body temperature was maintained at 39.0 ± 0.5°C in the normothermia group (NT, n = 8) and at 33.5 ± 0.5°C (24 h after the insult) in the TH (n = 7) and TH + EV (3 mg/kg intravenous every 12 h for 3 days after the insult; n = 6) groups under mechanical ventilation.

RESULTS

Five days after the insult, the mean (standard deviation) neurological scores were 10.9 (5.7) in the NT group, 17.0 (0.4) in the TH group (p = 0.025 vs. NT), and 15.0 (3.9) in the TH + EV group. The histopathological score of the TH + EV group showed no significant improvement compared with that of the other groups.

CONCLUSION

TH + EV had no additive neuroprotective effects after hypoxia-ischaemia in neurological and histopathological assessments.

Effects of Edaravone on Nitric Oxide, Hydroxyl Radicals and Neuronal Nitric Oxide Synthase During Cerebral Ischemia and Reperfusion in Mice

BACKGROUND

The purpose of this study was to investigate the effects of edaravone on nitric oxide (NO) production, hydroxyl radical (OH^-) metabolism, and neuronal nitric oxide synthase (nNOS) expression during cerebral ischemia and reperfusion.

METHODS

Edaravone (3 mg/kg) was administered intravenously to 14 C57BL/6 mice just before reperfusion. Eleven additional mice received saline (controls). NO production and OH^- metabolism were continuously monitored using bilateral striatal in vivo microdialysis. OH^- formation was monitored using the salicylate trapping method. Forebrain ischemia was produced in all mice by bilateral occlusion of the common carotid artery for 10 minutes. Levels of NO metabolites, nitrite (NO₂^-) and nitrate (NO₃^-), were determined using the Griess reaction. Brain sections were immunostained with an anti-nNOS antibody and the fractional area density of nNOS-immunoreactive pixels to total pixels determined.

RESULTS

Blood pressure and regional cerebral blood flow were not significantly different between the edaravone and control groups. The levels of NO₂^- did not differ significantly between the 2 groups. The level of NO₃^- was significantly higher in the edaravone group compared with the control group after reperfusion. 2,3-dihydroxybenzoic acid levels were lower in the edaravone group compared with those in the control group after reperfusion. Immunohistochemistry showed nNOS expression in the edaravone group to be significantly lower than that in the control group 96 hours after reperfusion.

CONCLUSIONS

These in vivo data indicate that edaravone may have a neuroprotective effect by reducing levels of OH^- metabolites, increasing NO production and decreasing nNOS expression in brain cells.

Synthesis, Characterization and Antioxidant Properties of a New Lipophilic Derivative of Edaravone

As part of a program aimed to obtain antioxidants able to interact with cell membrane, edaravone (EdV, 3-methyl-1-phenyl-2-pyrazolin-5-one), a well-known free radical scavenger, has been modified by alkylation at its allylic position (4) with a C-18 hydrocarbon chain, and the increased lipophilicity has been determined towards the interaction with liposomes. The obtained derivative has been studied by means of density functional theory (DFT) methods in order to characterize its lowest energy conformers and predict its antioxidant properties with respect to the parent compound EdV. The in vitro antioxidant activity of C18-edaravone was studied by means of the α,α-diphenyl-β-picrylhydrazyl (DPPH) assay and in lipid peroxidation experiments performed on artificial lipid membranes using water-soluble as well as lipid-soluble radical initiators. Moreover, since oxidative stress is involved in numerous retinal degenerative diseases, the ability of C18-edaravone to contrast 2,2-azobis (2-amidinopropane hydrochloride) (AAPH)-induced cell death was assessed in adult retinal pigmented epithelium (ARPE-19) cells. Overall, the results demonstrated that the newly synthesized molecule has a high affinity for lipid membrane, increasing the efficacy of the unmodified edaravone under stress conditions.

Protective effects of the astaxanthin derivative, adonixanthin, on brain hemorrhagic injury

Astaxanthin is beneficial for human health and is used as a dietary supplement. The present study was performed in order to examine the protective effects of the astaxanthin derivative, adonixanthin, against cell death caused by hemoglobin, collagenase, lipopolysaccharide, and hydrogen peroxide, which are associated with hemorrhagic brain injury. In an in vitro study, adonixanthin exerted cytoprotective effects against each type of damage, and its effects were stronger than those of astaxanthin. The increased production of reactive oxygen species in human brain endothelial cells in the hemoglobin treatment group was inhibited by adonixanthin. Moreover, adonixanthin suppressed cell death in SH-SY5Y cells. In an in vivo study, the oral administration of adonixanthin improved blood-brain barrier hyper-permeability in an autologous blood ICH model. We herein demonstrated for the first time that adonixanthin exerted protective effects against hemorrhagic brain damage by activating antioxidant defenses, and has potential as a protectant against intracerebral hemorrhage.

[Effects of interleukin 10 gene modified bone marrow mesenchymal stem cells on expression of inflammatory cytokines and neuronal apoptosis in rats after cerebral ischemia reperfusion injury]

Objective

To explore the effects of interleukin 10 (IL-10) gene modified bone marrow mesenchymal stem cells (BMSCs) on the expression of inflammatory cytokines and neuronal apoptosis in rats after cerebral ischemia reperfusion injury.

Methods

BMSCs were cultured by whole bone marrow adherence screening method. The properties of BMSCs were identified by immunocytochemical methods. BMSCs at passage 3 were transfected with recombinant adenovirus IL-10 gene (AdIL-10-BMSCs). The model of middle cerebral artery occlusion was made in 40 adult male Sprague Dawley rats by thread embolism method. The rats were randomly divided into 4 groups ( n=10). At 3 hours after modelling, the rats of groups A, B, C, and D received tail intravenous injection of 1 mL L-DMEM medium containing 10% FBS, 61.78 ng IL-10, 1 mL BMSCs suspension (2×10 ⁶ cells/mL), and 1 mL AdIL-10-BMSCs cell suspension (2×10 ⁶ cells/mL), respectively. The cells were labelled with BrdU before cell transplantation in groups C and D. At 7 days after reperfusion, the brain tissue was harvested to detect the expression of OX42 by immunohistochemical assay, to determine the concentration of tumor necrosis factor α (TNF-α) and IL-1β by ELISA, and to detect the apoptosis by TUNEL assay. BrdU labelled cells were observed by immunofluorescence staining in groups C and D.

Results

BrdU labelled positive cells with green fluorescence were observed in the brain tissue of groups C and D, which mainly distributed in the striatum, cerebral cortex, and subcortex around the infarction area. The number of OX42 positive cells was significantly less in groups B, C, and D than group A ( P<0.05), and in group D than groups B and C ( P<0.05). Compared with the other 3 groups, the contents of TNF-α and IL-1β significantly decreased in group D ( P<0.05). TUNEL assay showed that the apoptotic cells (TUNEL positive cells) were mainly seen in the striatum and fronto parietal subcortical tissues (equivalent to ischemic penumbra). The number of TUNEL positive cells in group D was significantly less than that in groups A, B, and C ( P<0.05).

Conclusion

AdIL-10-BMSCs can inhibit secretion of TNF-α and IL-1β from microglial cells and inhibit the nerve cell apoptosis around infarct brain tissue, which might contribute to its protective role upon cerebral ischemia reperfusion injury.

Protective effects of a radical scavenger edaravone on oligodendrocyte precursor cells against oxidative stress

Oligodendrocyte precursor cells (OPCs) play critical roles in maintaining the number of oligodendrocytes in white matter. Previously, we have shown that oxidative stress dampens oligodendrocyte regeneration after white matter damage, while a clinically proven radical scavenger, edaravone, supports oligodendrocyte repopulation. However, it is not known how edaravone exerts this beneficial effect against oxidative stress. Using in vivo and in vitro experiments, we have examined whether edaravone exhibits direct OPC-protective effects. For in vivo experiments, prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in mice. OPC damage was observed on day 14 after the onset of cerebral hypoperfusion, and edaravone was demonstrated to decrease OPC death in cerebral white matter. In vitro experiments also confirmed that edaravone reduced oxidative-stress-induced OPC death. Because white matter damage is a major hallmark of many neurological diseases, and OPCs are instrumental in white matter repair after injury, our current study supports the idea that radical scavengers may provide a potential therapeutic approach for white matter related diseases.

How is edaravone effective against acute ischemic stroke and amyotrophic lateral sclerosis?

Edaravone is a low-molecular-weight antioxidant drug targeting peroxyl radicals among many types of reactive oxygen species. Because of its amphiphilicity, it scavenges both lipid- and water-soluble peroxyl radicals by donating an electron to the radical. Thus, it inhibits the oxidation of lipids by scavenging chain-initiating water-soluble peroxyl radicals and chain-carrying lipid peroxyl radicals. In 2001, it was approved in Japan as a drug to treat acute-phase cerebral infarction, and then in 2015 it was approved for amyotrophic lateral sclerosis (ALS). In 2017, the U.S. Food and Drug Administration also approved edaravone for treatment of patients with ALS. Its mechanism of action was inferred to be scavenging of peroxynitrite. In this review, we focus on the radical-scavenging characteristics of edaravone in comparison with some other antioxidants that have been studied in clinical trials, and we summarize its pharmacological action and clinical efficacy in patients with acute cerebral infarction and ALS.

Edaravone attenuates oxidative stress induced by chronic cerebral hypoperfusion injury: role of ERK/Nrf2/HO-1 signaling pathway

Objectives The potential protective effects and mechanisms of edaravone have not been well elucidated in vascular dementia (VaD) induced by chronic cerebral hypoperfusion (CCH). The aim of this study was to investigate whether edaravone could improve cognitive damage in rats induced by CCH, and whether the effects of edaravone were associated with ERK/Nrf2/HO-1 signaling pathway. Methods CCH was induced by bilateral common carotid arteries occlusion (BCCAO). Sprague-Dawley (SD) rats were randomly divided into four groups: sham (sham-operated) group, vehicle (BCCAO + normal saline) group, edaravone3.0 group and edaravone6.0 group. The edaravone3.0 and edaravone6.0 group rats were provided 3.0 mg/kg and 6.0 mg/kg of edaravone, respectively, intraperitoneal (i.p.) injection twice daily following the first day after BCCAO. In this experiment, the spatial learning and memory were assessed using the Morris water maze. The malondialdehyde (MDA) contents and superoxide dismutase (SOD) activities in the hippocampus were measured biochemically. And, the levels of total ERK1/2 (t-ERK1/2), Phospho-ERK1/2 (p-ERK1/2), total Nrf2 (t-Nrf2), nuclear Nrf2 (n-Nrf2), and HO-1 were assessed by western blot. Results The results showed that the treatment with edaravone significantly improved CCH-induced cognitive damage, and boosted endogenous antioxidants SOD activity and HO-1 level, decreased MDA contents in the hippocampus by activating Nrf2 signaling pathway which was related to ERK1/2. We also found that the neuronal morphology of the hippocampal CA1 area significantly improved and the number of Nrf2 positive cells markedly increased in the edaravone treatment groups. Conclusion Our results demonstrated a neuroprotective effect of edaravone on hippocampus against oxidative stress and cognitive deficit induced by CCH. The mechanism may be related to the enhancement of antioxidant defense system by activating ERK/Nrf2/HO-1 signaling pathway.

A staged screening of registered drugs highlights remyelinating drug candidates for clinical trials

There is no treatment for the myelin loss in multiple sclerosis, ultimately resulting in the axonal degeneration that leads to the progressive phase of the disease. We established a multi-tiered platform for the sequential screening of drugs that could be repurposed as remyelinating agents. We screened a library of 2,000 compounds (mainly Food and Drug Administration (FDA)-approved compounds and natural products) for cellular metabolic activity on mouse oligodendrocyte precursors (OPC), identifying 42 molecules with significant stimulating effects. We then characterized the effects of these compounds on OPC proliferation and differentiation in mouse glial cultures, and on myelination and remyelination in organotypic cultures. Three molecules, edaravone, 5-methyl-7-methoxyisoflavone and lovastatin, gave positive results in all screening tiers. We validated the results by retesting independent stocks of the compounds, analyzing their purity, and performing dose-response curves. To identify the chemical features that may be modified to enhance the compounds' activity, we tested chemical analogs and identified, for edaravone, the functional groups that may be essential for its activity. Among the selected remyelinating candidates, edaravone appears to be of strong interest, also considering that this drug has been approved as a neuroprotective agent for acute ischemic stroke and amyotrophic lateral sclerosis in Japan.

Edaravone injection reverses learning and memory deficits in a rat model of vascular dementia

Edaravone is a novel free radical scavenger that exerts neuroprotective effects by inhibiting endothelial injury and by ameliorating neuronal damage in brain ischemia. Recently, it was reported that edaravone could alleviate the pathology and cognitive deficits of Alzheimer's disease patients. However, its relevance to vascular dementia (VaD) is not clear. In this study, we partially occluded the bilateral carotid arteries of rats surgically to induce chronic cerebral hypoperfusion (CCH), a well-known rat model of VaD. Water maze and step-down inhibitory test were used to evaluate the memory deficit. The activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH), the content of malondialdehyde (MDA) and total reactive oxygen species were measured to evaluate the oxidative stress level. Western blot analysis was used to evaluate the synaptic protein expression. It was found that treatment with edaravone for a 5-week period was able to reverse both spatial and fear-memory deficits in rats with CCH. Edaravone significantly reduced the level of oxidative stress in the brains of rats with CCH by increasing SOD activity and decreasing the content of MDA, LDH, and total reactive oxygen species. Furthermore, edaravone treatment also restored the levels of multiple synaptic proteins in the hippocampi of rats with CCH. Our data provide direct evidence supporting the neuroprotective effects of edaravone in VaD. We propose that the alleviation of oxidative stress and restoration of synaptic proteins play important roles in neuroprotection.

A free radical scavenger edaravone suppresses systemic inflammatory responses in a rat transient focal ischemia model

A free radical scavenger edaravone is clinically used in Japan for acute stroke, and several basic researches have carefully examined the mechanisms of edaravone's protective effects. However, its actions on pro-inflammatory responses under stroke are still understudied. In this study, we subjected adult male Sprague-Dawley rats to 90-min middle cerebral artery (MCA) occlusion followed by reperfusion. Edaravone was treated twice via tail vein; after MCA occlusion and after reperfusion. As expected, edaravone-treated group showed less infarct volume and edema formation compared with control group at 24-h after an ischemic onset. Furthermore, edaravone reduced the levels of plasma interleukin (IL)-1β and matrix metalloproteinase-9 at 3-h after ischemic onset. Several molecules besides IL-1β and MMP-9 are involved in inflammatory responses under stroke conditions. Therefore, we also examined whether edaravone treatment could decrease a wide range of pro-inflammatory cytokines/chemokines by testing rat plasma samples with a rat cytokine array. MCAO rats showed elevations in plasma levels of CINC-1, Fractalkine, IL-1α, IL-1ra, IL-6, IL-10, IP-10, MIG, MIP-1α, and MIP-3α, and all these increases were reduced by edaravone treatment. These data suggest that free radical scavengers may reduce systemic inflammatory responses under acute stroke conditions, and therefore, oxidative stress can be still a viable target for acute stroke therapy.

Analysis of treatment effect of urinary kallidinogenase combined with edaravone on massive cerebral infarction

The aim of the study was to investigate the clinical effect of urinary kallidinogenase combined with edaravone in the treatment of massive cerebral infarction. A total of 58 patients with massive cerebral infarction were admitted to hospital between January 2013 and January 2014. There were 34 male and 24 female patients. The patients were randomly divided into the observation and control groups (n=29 cases per group). The patients in the control group received edaravone treatment, while patients in the observation group were treated with urinary kallidinogenase and edaravone. The clinical effects of the two groups were then compared. The results showed that the National Institutes of Health Stroke Scale score and serum C-reactive protein level of the patients in the two groups were significantly decreased following treatment. The decreased degree in the observation group was significantly smaller than that in the control group. The difference was statistically significant [(11.03±3.75) vs. (16.58±7.43) scores, P<0.05; (9.88±4.82) vs. (11.98±4.69) mmol/l, P<0.05]. The serum levels of vascular endothelial growth factor were significantly increased in patients of the two groups after treatment. The increased degree in the observation group was significantly higher than that in the control group. The difference was statistically significant [(268.51±77.34) vs. (188.82±57.33) ng/l, P<0.05]. The total effective rate of the observation group was significantly higher than that of the control group and the difference was statistically significant (89.66 vs. 62.07%, P<0.05). In conclusion, urinary kallidinogenase combined with edaravone treatment has a certain clinical curative effect on massive cerebral infarction.

Edaravone Reduces Hyperperfusion-Related Neurological Deficits in Adult Moyamoya Disease

Background and Purpose—

Postoperative hyperperfusion-related transient neurological deficits (TNDs) are frequently observed in adult patients with moyamoya disease who undergo direct bypass procedures. The present study evaluated the effect of the free radical scavenger edaravone on postoperative hyperperfusion in adult moyamoya disease.

Methods—

This study included 92 hemispheres in 72 adult patients who underwent direct bypass for moyamoya disease. Serial measurements of cerebral blood flow were conducted immediately after surgery and on postoperative days 2 and 7. In 40 hemispheres for 36 patients, edaravone (60 mg/d) was administered from the day of surgery to postsurgical day 7. The incidence of postoperative hyperperfusion and associated TNDs were compared with a control group that included 52 hemispheres in 36 patients.

Results—

Radiological hyperperfusion was observed in 28 of 40 (70.0%) and 39 of 52 (75.0%) hemispheres in the edaravone and control groups, respectively ( P =0.30). Hyperperfusion-related TND incidences were significantly lower in the edaravone group compared with the control group (12.5% versus 32.7%; P =0.024). Multivariate analysis demonstrated that edaravone administration ( P =0.009) and left-sided surgery ( P =0.037) were significantly correlated with hyperperfusion-related TNDs (odds ratios, 0.3 and 4.2, respectively).

Conclusions—

Perioperative administration of edaravone reduced the incidence of hyperperfusion-related TNDs after direct bypass procedures in adult patients with moyamoya disease.

Edaravone is a free radical scavenger that protects against laser-induced choroidal neovascularization in mice and common marmosets

Choroidal neovascularization (CNV) is a main characteristic in exudative type of age-related macular degeneration (AMD). Our study aimed to evaluate the effects of edaravone, a free radical scavenger on laser-induced CNV. CNV was induced by laser photocoagulation to the subretinal choroidal area of mice and common marmosets. Edaravone was administered either intraperitoneally twice a day for 2 weeks or intravenously just once after laser photocoagulation. The effects of edaravone on laser-induced CNV were evaluated by fundus fluorescein angiography, CNV area measurements, and the expression of 4-hydroxy-2-nonenal (4-HNE) modified proteins, a marker of oxidative stress. Furthermore, the effects of edaravone on the production of H2O2-induced reactive oxygen species (ROS) and vascular endothelial growth factor (VEGF)-induced cell proliferation were evaluated using human retinal pigment epithelium cells (ARPE-19) and human retinal microvascular endothelial cells, respectively. CNV areas in the edaravone-treated group were significantly smaller in mice and common marmosets. The expression of 4-HNE modified proteins was upregulated 3 h after laser photocoagulation, and intravenously administered edaravone decreased it. In in vitro studies, edaravone inhibited H2O2-induced ROS production and VEGF-induced cell proliferation. These findings suggest that edaravone may protect against laser-induced CNV by inhibiting oxidative stress and endothelial cell proliferation.

Edaravone offers neuroprotection for acute diabetic stroke patients

INTRODUCTION

Edaravone, a novel free-radical scavenger, has been shown to alleviate cerebral ischemic injury and protect against vascular endothelial dysfunction. However, the effects of edaravone in acute diabetic stroke patients remain undetermined.

METHODS

A randomized, double-blind, placebo-controlled study was performed to prospectively evaluate the effects of edaravone on acute diabetic stroke patients admitted to our hospital within 24 h of stroke onset. The edaravone group received edaravone (30 mg twice per day) diluted with 100 ml of saline combined with antiplatelet drug aspirin and atorvastatin for 14 days. The non-edaravone group was treated only with 100 ml of saline twice per day combined with aspirin and atorvastatin. Upon admission, and on days 7, 14 post-stroke onset, neurological deficits and activities of daily living were assessed using the National Institutes of Health Stroke Scale (NIHSS) and the Barthel Index (BI), respectively. The occurrence of hemorrhage transformation, pulmonary infection, progressive stroke and epilepsy was also evaluated on day 14 post-treatment.

RESULTS

A total of 65 consecutive acute diabetic stroke patients were enrolled, of whom 35 were allocated to the edaravone group and 30 to the non-edaravone group. There was no significant group difference in baseline clinical characteristics, but mean NIHSS scores were lower (60 %), and BI scores were 1.7-fold higher, in edaravone-treated patients vs. controls on day 14. Furthermore, the incidence of hemorrhage transformation, pulmonary infection, progressive stroke and epilepsy was markedly reduced in the edaravone vs. non-edaravone group.

CONCLUSION

Edaravone represents a promising neuroprotectant against cerebral ischemic injury in diabetic patients.

Edaravone leads to proteome changes indicative of neuronal cell protection in response to oxidative stress

Neuronal cell death, in neurodegenerative disorders, is mediated through a spectrum of biological processes. Excessive amounts of free radicals, such as reactive oxygen species (ROS), has detrimental effects on neurons leading to cell damage via peroxidation of unsaturated fatty acids in the cell membrane. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been used for neurological recovery in several countries, including Japan and China, and it has been suggested that Edaravone may have cytoprotective effects in neurodegeneration. Edaravone protects nerve cells in the brain by reducing ROS and inhibiting apoptosis. To gain further insight into the cytoprotective effects of Edaravone against oxidative stress condition we have performed comparative two-dimensional gel electrophoresis (2DE)-based proteomic analyses on SH-SY5Y neuroblastoma cells exposed to oxidative stress and in combination with Edaravone. We showed that Edaravone can reverse the cytotoxic effects of H2O2 through its specific mechanism. We observed that oxidative stress changes metabolic pathways and cytoskeletal integrity. Edaravone seems to reverse the H2O2-mediated effects at both the cellular and protein level via induction of Peroxiredoxin-2.

Prophylactic Edaravone Prevents Transient Hypoxic-Ischemic Brain Injury: Implications for Perioperative Neuroprotection

BACKGROUND AND PURPOSE

Hypoperfusion-induced thrombosis is an important mechanism for postsurgery stroke and cognitive decline, but there are no perioperative neuroprotectants to date. This study investigated whether prophylactic application of Edaravone, a free radical scavenger already used in treating ischemic stroke in Japan, can prevent infarct and cognitive deficits in a murine model of transient cerebral hypoxia-ischemia.

METHODS

Adult male C57BL/6 mice were subjected to transient hypoxic-ischemic (tHI) insult that consists of 30-minute occlusion of the unilateral common carotid artery and exposure to 7.5% oxygen. Edaravone or saline was prophylactically applied to compare their effects on cortical oxygen saturation, blood flow, coagulation, oxidative stress, metabolites, and learning-memory using methods that include photoacoustic imaging, laser speckle contrast imaging, solid-state NMR, and Morris water maze. The effects on infarct size by Edaravone application at different time points after tHI were also compared.

RESULTS

Prophylactic administration of Edaravone (4.5 mg/kg×2, IP, 1 hour before and 1 hour after tHI) improved vascular reperfusion, oxygen saturation, and the maintenance of brain metabolites, reducing oxidative stress, thrombosis, white-matter injury, and learning impairment after tHI insult. Delayed Edaravone treatment after 3 h post-tHI became unable to reduce infarct size.

CONCLUSIONS

Acute application of Edaravone may be a useful strategy to prevent postsurgery stroke and cognitive impairment, especially in patients with severe carotid stenosis.

Changes in cerebrospinal fluid biomarkers in human herpesvirus-6-associated acute encephalopathy/febrile seizures

To determine the involvement of oxidative stress in the pathogenesis of acute encephalopathy associated with human herpesvirus-6 (HHV-6) infection, we measured the levels of oxidative stress markers 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hexanoyl-lysine adduct (HEL), tau protein, and cytokines in cerebrospinal fluid (CSF) obtained from patients with HHV-6-associated acute encephalopathy (HHV-6 encephalopathy) (n = 16) and complex febrile seizures associated with HHV-6 (HHV-6 complex FS) (n = 10). We also examined changes in CSF-8OHdG and CSF-HEL levels in patients with HHV-6 encephalopathy before and after treatment with edaravone, a free radical scavenger. CSF-8-OHdG levels in HHV-6 encephalopathy and HHV-6 complex FS were significantly higher than in control subjects. In contrast, CSF-HEL levels showed no significant difference between groups. The levels of total tau protein in HHV-6 encephalopathy were significantly higher than in control subjects. In six patients with HHV-6 infection (5 encephalopathy and 1 febrile seizure), the CSF-8-OHdG levels of five patients decreased after edaravone treatment. Our results suggest that oxidative DNA damage is involved in acute encephalopathy associated with HHV-6 infection.

Synergy of combined tPA-edaravone therapy in experimental thrombotic stroke

Edaravone, a potent antioxidant, may improve thrombolytic therapy because it benefits ischemic stroke patients on its own and mitigates adverse effects of tissue plasminogen activator (tPA) in preclinical models. However, whether the combined tPA-edaravone therapy is more effective in reducing infarct size than singular treatment is uncertain. Here we investigated this issue using a transient hypoxia-ischemia (tHI)-induced thrombotic stroke model, in which adult C57BL/6 mice were subjected to reversible ligation of the unilateral common carotid artery plus inhalation of 7.5% oxygen for 30 min. While unilateral occlusion of the common carotid artery suppressed cerebral blood flow transiently, the addition of hypoxia triggered reperfusion deficits, endogenous thrombosis, and attenuated tPA activity, leading up to infarction. We compared the outcomes of vehicle-controls, edaravone treatment, tPA treatment at 0.5, 1, or 4 h post-tHI, and combined tPA-edaravone therapies with mortality rate and infarct size as the primary end-points. The best treatment was further compared with vehicle-controls in behavioral, biochemical, and diffusion tensor imaging (DTI) analyses. We found that application of tPA at 0.5 or 1 h – but not at 4 h post-tHI – significantly decreased infarct size and showed synergistic (p<0.05) or additive benefits with the adjuvant edaravone treatment, respectively. The acute tPA-edaravone treatment conferred >50% reduction of mortality, ∼80% decline in infarct size, and strong white-matter protection. It also improved vascular reperfusion and decreased oxidative stress, inflammatory cytokines, and matrix metalloproteinase activities. In conclusion, edaravone synergizes with acute tPA treatment in experimental thrombotic stroke, suggesting that clinical application of the combined tPA-edaravone therapy merits investigation.

Edaravone protect against retinal damage in streptozotocin-induced diabetic mice

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, is used for the clinical treatment of retinal injury. In this study, we investigated the protective effects of edaravone against diabetic retinal damage in the mouse. Diabetic retinopathy in the mouse was induced by injection of streptozotocin. Edaravone was given once-daily and was intraperitoneally (i.p.) treated at a dose of 3 mg/kg from streptozotocin injection to 4 weeks after onset of diabetes. Retinal ganglion cells (RGCs) damage was evaluated by recording the pattern electroretinogram (ERG). RGCs damage was also detected by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, and the levels of reactive oxygen species (ROS) were determined fluorometrically. The expressions of phosporylated-ERK1/2, BDNF, and caspase-3 were determined by Western blot analysis. Retinal levels of ROS, phosphorylated ERK1/2, and cleaved caspase-3 were significantly increased, whereas the expression of BDNF was significantly decreased in the retinas of diabetic mice, compared to nondiabetic mice. Administration of edaravone significantly attenuated diabetes induced RGCs death, upregulation of ROS, ERK1/2 phosphorylation, and cleaved caspase-3 and downregulation of BDNF. These findings suggest that oxidative stress plays a pivotal role in diabetic retinal damage and that systemic administration of edaravone may slow the progression of retinal neuropathy induced by diabetes.

A radical scavenger edaravone inhibits matrix metalloproteinase-9 upregulation and blood-brain barrier breakdown in a mouse model of prolonged cerebral hypoperfusion

Matrix metalloproteinase-9 (MMP-9) plays key roles in the brain pathophysiology, especially in blood-brain barrier (BBB) breakdown. Therefore, inhibiting MMP-9 activity may be a promising therapy for protecting brains in cerebrovascular diseases. Here we show that in a mouse prolonged cerebral hypoperfusion model, a clinically proven radical scavenger edaravone suppressed MMP-9 and reduced BBB damage in cerebral white matter. Prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in male adult C57BL/6J mice (10 weeks old). After 7 days of cerebral hypoperfusion, white matter region (e.g. corpus callosum) exhibited significant BBB leakage, assessed by IgG staining. Correspondingly, immunostaining and western blotting showed that MMP-9 was upregulated in the white matter. Edaravone treatment (3mg/kg, i.p. at days 0 and 3) inhibited both BBB leakage and MMP-9 increase. Under the early phase of cerebral hypoperfusion conditions, oligodendrocyte precursor cells (OPCs) mainly contribute to the MMP-9 increase, but our immunostaining data showed that very little OPCs expressed MMP-9 in the edaravone-treated animals at day 7. Therefore, in vitro studies with primary rat OPCs were conducted to examine whether edaravone would directly suppressed MMP-9 expressions in OPCs. OPC cultures were exposed to sub-lethal CoCl2 for 7 days to induce prolonged chemical hypoxic stress. Prolonged chemical hypoxic stress increased MMP-9 expression in OPCs, and radical scavenging with edaravone (10μM for 7 days) ameliorated the increase. Taken together, our proof-of-concept study demonstrates that radical scavengers may provide a potential therapeutic approach for white matter injury by suppressing BBB damage.

Oligodendrocyte pathophysiology and treatment strategies in cerebral ischemia

Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, form a functional unit with axons and play a crucial role in axonal integrity. An episode of hypoxia-ischemia causes rapid and severe damage to these particularly vulnerable cells via multiple pathways such as overactivation of glutamate and ATP receptors, oxidative stress, and disruption of mitochondrial function. The cardinal effect of OL pathology is demyelination and dysmyelination, and this has profound effects on axonal function, transport, structure, metabolism, and survival. The OL is a primary target of ischemia in adult-onset stroke and especially in periventricular leukomalacia and should be considered as a primary therapeutic target in these conditions. More emphasis is needed on therapeutic strategies that target OLs, myelin, and their receptors, as these have the potential to significantly attenuate white matter injury and to establish functional recovery of white matter after stroke. In this review, we will summarize recent progress on the role of OLs in white matter ischemic injury and the current and emerging principles that form the basis for protective strategies against OL death.

Lipoxygenase: an emerging target for stroke therapy

Neuroprotection as approach to stroke therapy has recently seen a revival of sorts, fueled in part by the continuing necessity to improve acute stroke care, and in part by the identification of novel drug targets. 12/15- Lipoxygenase (12/15-LOX), one of the key enzymes of the arachidonic acid cascade, contributes to both neuronal cell death and vascular injury. Inhibition of 12/15-LOX may thus provide multifactorial protection against ischemic injury. Targeting 12/15-LOX and related eicosanoid pathways is the subject of this brief review.

Edaravone Improves Functional and Structural Outcomes in Animal Models of Focal Cerebral Ischemia: A Systematic Review

Edaravone has been used in patients with acute ischemic stroke in Japan for over 10 years but does not have marketing authorization in Europe or America. Either patients in Europe and America are not receiving an effective treatment, or those in Asia are being given a treatment which is not effective. Finding out which of these is true will require further clinical trials, and a better understanding of its efficacy in animal models may help inform the design of those trials so that it might be tested under conditions where there is the greatest prospect of success. We systematically reviewed the efficacy of edaravone in animal models of focal ischemia and summarized data using weighted mean difference DerSimonian and Laird random-effects modeling. We used stratified meta-analysis and metaregression to assess the influence of study design and methodological quality. We identified 49 experiments describing outcome in 814 animals; 30 experiments (519 animals) reported functional and 35 experiments (503 animals) reported structural outcome. Edaravone improved functional and structural outcome by 30.3% (95% confidence interval 23.4–37.2%) and 25.5% (95% confidence interval, 21.1–29.9%), respectively. For functional outcome, there was an inverse relationship between study quality and effect size ( P < 0.0017). Effect sizes were larger in studies where randomization or blinded assessment was not reported. There was no evidence of publication bias. Edaravone is a promising treatment for stroke. However, because of the methodological weakness in current animal studies, no sufficient preclinical evidence is available to optimize the study design of clinical trials. Higher quality animal studies are expected to inform further clinical study.

Oxidative stress interferes with white matter renewal after prolonged cerebral hypoperfusion in mice

BACKGROUND AND PURPOSE

White matter injury caused by cerebral hypoperfusion may contribute to the pathophysiology of vascular dementia and stroke, but the underlying mechanisms remain to be fully defined. Here, we test the hypothesis that oxidative stress interferes with endogenous white matter repair by disrupting renewal processes mediated by oligodendrocyte precursor cells (OPCs).

METHODS

In vitro, primary rat OPCs were exposed to sublethal CoCl2 for 7 days to induce prolonged chemical hypoxic stress. Then, OPC proliferation/differentiation was assessed. In vivo, prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in mice. Then, reactive oxygen species production, myelin density, oligodendrocyte versus OPC counts, and cognitive function were evaluated. To block oxidative stress, OPCs and mice were treated with the radical scavenger edaravone.

RESULTS

Prolonged chemical hypoxic stress suppressed OPC differentiation in vitro. Radical scavenging with edaravone ameliorated these effects. After 28 days of cerebral hypoperfusion in vivo, reactive oxygen species levels were increased in damaged white matter, along with the suppression of OPC-to-oligodendrocyte differentiation and loss of myelin staining. Concomitantly, mice showed functional deficits in working memory. Radical scavenging with edaravone rescued OPC differentiation, ameliorated myelin loss, and restored working memory function.

CONCLUSIONS

Our proof-of-concept study demonstrates that after prolonged cerebral hypoperfusion, oxidative stress interferes with white matter repair by disrupting OPC renewal mechanisms. Radical scavengers may provide a potential therapeutic approach for white matter injury in vascular dementia and stroke.

Nitric oxide donors as neuroprotective agents after an ischemic stroke-related inflammatory reaction

Cerebral ischemia initiates a cascade of detrimental events including glutamate-associated excitotoxicity, intracellular calcium accumulation, formation of Reactive oxygen species (ROS), membrane lipid degradation, and DNA damage, which lead to the disruption of cellular homeostasis and structural damage of ischemic brain tissue. Cerebral ischemia also triggers acute inflammation, which exacerbates primary brain damage. Therefore, reducing oxidative stress (OS) and downregulating the inflammatory response are options that merit consideration as potential therapeutic targets for ischemic stroke. Consequently, agents capable of modulating both elements will constitute promising therapeutic solutions because clinically effective neuroprotectants have not yet been discovered and no specific therapy for stroke is available to date. Because of their ability to modulate both oxidative stress and the inflammatory response, much attention has been focused on the role of nitric oxide donors (NOD) as neuroprotective agents in the pathophysiology of cerebral ischemia-reperfusion injury. Given their short therapeutic window, NOD appears to be appropriate for use during neurosurgical procedures involving transient arterial occlusions, or in very early treatment of acute ischemic stroke, and also possibly as complementary treatment for neurodegenerative diseases such as Parkinson or Alzheimer, where oxidative stress is an important promoter of damage. In the present paper, we focus on the role of NOD as possible neuroprotective therapeutic agents for ischemia/reperfusion treatment.

Edaravone alleviates hypoxia-acidosis/reoxygenation-induced neuronal injury by activating ERK1/2

Edaravone, a free radical scavenger, is the first clinical drug of neuroprotection for ischemic stroke patients in the world, and has been shown to be an effective agent to alleviate cerebral ischemic injury. It has been established that acidosis is a common feature of cerebral ischemia and underlies the pathogenesis of ischemic stroke. In the present study, we investigated the role of edaravone in hypoxia-acidosis/reoxygenation (H-A/R)-induced neuronal injury that is partially mediated by the activation of acid-sensing ion channels (ASICs). Here, we observed that pretreatment of cultured neurons with edaravone largely reduced LDH release induced by acidosis or H-A/R. We also found that edaravone exhibited its neuroprotective roles by enhancing brain-derived neurotrophic factor (BDNF) and Bcl-2 expression, suppressing caspase-3 activity and promoting extracellular signal-regulated kinase1/2 (ERK1/2) activation. Furthermore, the addition of MEK (mitogen-activated protein kinase/ERK kinase) antagonists PD98059 and U0126 nearly abolished the beneficial effects of edaravone. Similarly, ASICs blockade produced the protective effects comparable to edaravone administration. These results indicate that edaravone is capable of attenuating H-A/R-mediated neurotoxicity at least partially through activating ERK1/2.

Edaravone increases regional cerebral blood flow after traumatic brain injury in mice

Traumatic brain injury (TBI) is a major cause of preventable death and serious morbidity, with subsequent low cerebral blood flow (CBF) considered to be associated with poor prognosis. In the present study, we demonstrated the effect of the free radical scavenger edaravone on regional CBF (rCBF) after TBI. Male mice (C57/BL6) were subjected to TBI using a controlled cortical impactor device. Immediately after TBI, the animals were intravenously administered 3.0 mg/kg of edaravone or a vehicle saline solution. Two-dimensional rCBF images were acquired before and 24 h post-TBI, and were quantified in the ipsilateral and contralateral hemispheres (n = 5 animals per group). CBF in the vehicle-treated animals decreased broadly over the ipsilateral hemisphere, with the region of low rCBF spreading from the frontal cortex to the occipital lobe. The zone of lowest rCBF matched that of the contusion area. The mean rCBF at 24 h for a defined elliptical region between the bregma and lambda was 73.7 ± 5.8 %. In comparison, the reduction of rCBF in edaravone-treated animals was significantly attenuated (93.4 ± 5.7 %, p < 0.05). The edaravone-treated animals also exhibited higher rCBF in the contralateral hemisphere compared with that seen in -vehicle-treated animals. It is suggested that edaravone reduces neuronal damage by scavenging reactive oxygen species (ROS) and by maintaining intact the autoregulation of the cerebral vasculature.

Effects of edaravone on muscle atrophy and locomotor function in patients with ischemic stroke: a randomized controlled pilot study

BACKGROUND AND OBJECTIVE

Stroke patients with severe leg paralysis are often bedridden in the acute and subacute phase, which increases the risk of disuse muscle atrophy in the chronic phase. The evidence to date indicates that oxidative stress plays an important role in the mechanism of disuse muscle atrophy. Therefore, the aim of this study was to determine if long-term radical scavenger treatment with edaravone following an acute stroke prevents the progression of disuse muscle atrophy and improves leg locomotor function in the chronic phase.

METHODS

This randomized controlled pilot study was conducted at 19 acute stroke and rehabilitation centers across Japan. Forty-seven ischemic stroke patients with at least leg motor weakness admitted within 24 hours of onset were randomly assigned to receive continuous intravenous infusions of edaravone 30 mg twice daily for 3 days (short-term group) or 10-14 days (long-term group). The primary endpoints of the study included the degree of leg disuse muscle atrophy, as measured by the percentage change from baseline in femoral muscle circumference 15 cm above the knee, and the improvement in leg locomotor function, as assessed by the maximum walking speed over 10 m, 3 months after the onset of stroke.

RESULTS

Three-month follow-up was completed by a total of 41 patients (21 in the short-term group and 20 in the long-term group). On admission, there was no significant difference in the severity of stroke or the grade of leg paresis between the two treatment groups. The grade of disuse muscle atrophy and incidence of gait impairment 3 weeks after stroke onset were also similar between the short- and long-term groups. However, disuse muscle atrophy of the paretic and non-paretic legs was significantly less severe in the long-term versus the short-term treatment group (3.6 ± 5.9% and 1.5 ± 6.0% vs 8.3 ± 5.2% and 5.7 ± 6.4%; p < 0.01 and p < 0.05) 3 months after stroke onset. Additionally, the maximum walking speed over a distance of 10 m was significantly greater in the long-term group (98 ± 67 vs 54 ± 55 cm/sec; p < 0.05).

CONCLUSION

Edaravone treatment for up to 14 days suppresses the progression of disuse muscle atrophy and improves leg locomotor function to a greater extent than shorter-term treatment in acute stroke patients. This suggests that the management of stroke may be improved with long-term edaravone therapy by providing myoprotective effects that ameliorate functional outcome in the chronic phase.

Neuroinflammation and cerebrovascular disease in old age: a translational medicine perspective

The incidence of cerebrovascular disease is highest in the elderly population. However, the pathophysiological mechanisms of brain response to cerebral ischemia in old age are currently poorly understood. Ischemic changes in the commonly used young animal stroke models do not reflect the molecular changes associated with the aged brain. Neuroinflammation and oxidative stress are important pathogenic processes occurring during the acute phase of cerebral ischemia. Free radical generation is also implicated in the aging process, and the combination of these effects in elderly stroke patients could explain the higher risk of morbidity and mortality. A better understanding of stroke pathophysiology in the elderly patient would assist in the development of new therapeutic strategies for this vulnerable age group. With the increasing use of reperfusion therapies, inflammatory pathways and oxidative stress remain attractive therapeutic targets for the development of adjuvant neuroprotective agents. This paper will discuss these molecular aspects of acute stroke and senescence from a bench-to-bedside research perspective.